reference/apis/js-apis-effectKit.md

# @ohos.effectKit (Image Effects)

The **EffectKit** module provides basic image processing capabilities, including brightness adjustment, blurring, grayscale adjustment, and color picker.

This module provides the following classes:

- [Filter](#filter): a class that adds a specified effect to the image source.
- [Color](#color): a class used to store the color picked.
- [ColorPicker](#colorpicker): a smart color picker.

> **NOTE**
>
> The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.

## Modules to Import

```ts
import effectKit from '@ohos.effectKit';
```

## effectKit.createEffect
createEffect(source: image.PixelMap): Filter

Creates a **Filter** instance based on a pixel map.

**System capability**: SystemCapability.Multimedia.Image.Core

**Parameters**

| Name   | Type              | Mandatory| Description    |
| ------- | ----------------- | ---- | -------- |
| source  | [image.PixelMap](js-apis-image.md#pixelmap7) | Yes  | **PixelMap** instance created by the image module. An instance can be obtained by decoding an image or directly created. For details, see [Image Overview](../../media/image-overview.md).  |

**Return value**

| Type                            | Description          |
| -------------------------------- | -------------- |
| [Filter](#filter) | Head node of the filter linked list without any effect. If the operation fails, **null** is returned.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  let headFilter = effectKit.createEffect(pixelMap);
})
```

## effectKit.createColorPicker

createColorPicker(source: image.PixelMap): Promise\<ColorPicker>

Creates a **ColorPicker** instance based on a pixel map. This API uses a promise to return the result.

**System capability**: SystemCapability.Multimedia.Image.Core

**Parameters**

| Name    | Type        | Mandatory| Description                      |
| -------- | ----------- | ---- | -------------------------- |
| source   | [image.PixelMap](js-apis-image.md#pixelmap7) | Yes  |  **PixelMap** instance created by the image module. An instance can be obtained by decoding an image or directly created. For details, see [Image Overview](../../media/image-overview.md).|

**Return value**

| Type                  | Description          |
| ---------------------- | -------------- |
| Promise\<[ColorPicker](#colorpicker)>  | Promise used to return the **ColorPicker** instance created.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}

image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap).then(colorPicker => {
    console.info("color picker=" + colorPicker);
  }).catch( (reason : BusinessError) => {
    console.error("error=" + reason.message);
  })
})
```

## effectKit.createColorPicker<sup>10+</sup>

createColorPicker(source: image.PixelMap, region: Array\<number>): Promise\<ColorPicker>

Creates a **ColorPicker** instance for the selected region based on a pixel map. This API uses a promise to return the result.

**System capability**: SystemCapability.Multimedia.Image.Core

**Parameters**

| Name    | Type        | Mandatory| Description                      |
| -------- | ----------- | ---- | -------------------------- |
| source   | [image.PixelMap](js-apis-image.md#pixelmap7) | Yes  |  **PixelMap** instance created by the image module. An instance can be obtained by decoding an image or directly created. For details, see [Image Overview](../../media/image-overview.md).|
| region   | Array\<number> | Yes  |  Region of the image from which the color is picked.<br>The array consists of four elements, representing the left, top, right, and bottom positions of the image, respectively. The value of each element must be in the range [0, 1]. The leftmost and topmost positions of the image correspond to 0, and the rightmost and bottom positions correspond to 1. In the array, the third element must be greater than the first element, and the fourth element must be greater than the second element.<br>If no value is passed, the default value [0, 0, 1, 1] is used, indicating that the color region is the entire image.|

**Return value**

| Type                  | Description          |
| ---------------------- | -------------- |
| Promise\<[ColorPicker](#colorpicker)>  | Promise used to return the **ColorPicker** instance created.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}

image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap).then(colorPicker => {
    console.info("color picker=" + colorPicker);
  }).catch( (reason : BusinessError) => {
    console.error("error=" + reason.message);
  })
})
```

## effectKit.createColorPicker

createColorPicker(source: image.PixelMap, callback: AsyncCallback\<ColorPicker>): void

Creates a **ColorPicker** instance based on a pixel map. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.Multimedia.Image.Core

**Parameters**

| Name    | Type               | Mandatory| Description                      |
| -------- | ------------------ | ---- | -------------------------- |
| source   | [image.PixelMap](js-apis-image.md#pixelmap7) | Yes |**PixelMap** instance created by the image module. An instance can be obtained by decoding an image or directly created. For details, see [Image Overview](../../media/image-overview.md). |
| callback | AsyncCallback\<[ColorPicker](#colorpicker)> | Yes | Callback used to return the **ColorPicker** instance created.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
    }
  })
})
```

## effectKit.createColorPicker<sup>10+</sup>

createColorPicker(source: image.PixelMap, region:Array\<number>, callback: AsyncCallback\<ColorPicker>): void

Creates a **ColorPicker** instance for the selected region based on a pixel map. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.Multimedia.Image.Core

**Parameters**

| Name    | Type               | Mandatory| Description                      |
| -------- | ------------------ | ---- | -------------------------- |
| source   | [image.PixelMap](js-apis-image.md#pixelmap7) | Yes |**PixelMap** instance created by the image module. An instance can be obtained by decoding an image or directly created. For details, see [Image Overview](../../media/image-overview.md). |
| region   | Array\<number> | Yes  |  Region of the image from which the color is picked.<br>The array consists of four elements, representing the left, top, right, and bottom positions of the image, respectively. The value of each element must be in the range [0, 1]. The leftmost and topmost positions of the image correspond to 0, and the rightmost and bottom positions correspond to 1. In the array, the third element must be greater than the first element, and the fourth element must be greater than the second element.<br>If no value is passed, the default value [0, 0, 1, 1] is used, indicating that the color region is the entire image.|
| callback | AsyncCallback\<[ColorPicker](#colorpicker)> | Yes | Callback used to return the **ColorPicker** instance created.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
    }
  })
})
```

## Color

A class that stores the color picked.

**System capability**: SystemCapability.Multimedia.Image.Core

| Name  | Type  | Readable| Writable| Description             |
| ------ | ----- | ---- | ---- | ---------------- |
| red   | number | Yes  | No  | Value of the red component. The value range is [0x0, 0xFF].          |
| green | number | Yes  | No  | Value of the green component. The value range is [0x0, 0xFF].          |
| blue  | number | Yes  | No  | Value of the blue component. The value range is [0x0, 0xFF].          |
| alpha | number | Yes  | No  | Value of the alpha component. The value range is [0x0, 0xFF].      |

## ColorPicker

A class used to obtain the color from an image. Before calling any method of **ColorPicker**, use [createColorPicker](#effectkitcreatecolorpicker) to create a **ColorPicker** instance.

### getMainColor

getMainColor(): Promise\<Color>

Obtains the main color from the image and writes the result to a [Color](#color) instance. This API uses a promise to return the result.

**System capability**: SystemCapability.Multimedia.Image.Core

**Return value**

| Type          | Description                                           |
| :------------- | :---------------------------------------------- |
| Promise\<[Color](#color)> | Promise used to return the color value of the main color. If the operation fails, an error message is returned.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

export function test06(): void {
  const color = new ArrayBuffer(96);
  let opts: image.InitializationOptions = {
    editable: true,
    pixelFormat: 3,
    size: {
      height: 4,
      width: 6
    }
  }
  image.createPixelMap(color, opts).then((pixelMap) => {
    effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
      if (error) {
        console.log('Failed to create color picker.');
      } else {
        console.log('Succeeded in creating color picker.');
        colorPicker.getMainColor().then(color => {
          console.log('Succeeded in getting main color.');
          console.info(`color[ARGB]=${color.alpha},${color.red},${color.green},${color.blue}`);
        })
      }
    })
  })
}
```

### getMainColorSync

getMainColorSync(): Color

Obtains the main color from the image and writes the result to a [Color](#color) instance. This API returns the result in synchronous mode.

**System capability**: SystemCapability.Multimedia.Image.Core

**Return value**

| Type    | Description                                 |
| :------- | :----------------------------------- |
| [Color](#color)    | Color value of the main color. If the operation fails, **null** is returned.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
      let color = colorPicker.getMainColorSync();
      console.log('get main color =' + color);
    }
  })
})
```
![en-us_image_Main_Color.png](figures/en-us_image_Main_Color.png)

### getLargestProportionColor<sup>10+</sup>

getLargestProportionColor(): Color

Obtains the color with the largest proportion from the image and writes the result to a [Color](#color) instance. This API returns the result in synchronous mode.

**System capability**: SystemCapability.Multimedia.Image.Core

**Return value**

| Type          | Description                                           |
| :------------- | :---------------------------------------------- |
| [Color](#color)       | Color value of the color with the largest proportion. If the operation fails, **null** is returned.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
      let color = colorPicker.getLargestProportionColor();
      console.log('get largest proportion color =' + color);
    }
  })
})
```
![en-us_image_Largest_Proportion_Color.png](figures/en-us_image_Largest_Proportion_Color.png)

### getHighestSaturationColor<sup>10+</sup>

getHighestSaturationColor(): Color

Obtains the color with the highest saturation from the image and writes the result to a [Color](#color) instance. This API returns the result in synchronous mode.

**System capability**: SystemCapability.Multimedia.Image.Core

**Return value**

| Type          | Description                                           |
| :------------- | :---------------------------------------------- |
| [Color](#color)       | Color value of the color with the highest saturation. If the operation fails, **null** is returned.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts: image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
      let color = colorPicker.getHighestSaturationColor();
      console.log('get highest saturation color =' + color);
    }
  })
})
```
![en-us_image_Highest_Saturation_Color.png](figures/en-us_image_Highest_Saturation_Color.png)

### getAverageColor<sup>10+</sup>

getAverageColor(): Color

Obtains the average color from the image and writes the result to a [Color](#color) instance. This API returns the result in synchronous mode.

**System capability**: SystemCapability.Multimedia.Image.Core

**Return value**

| Type          | Description                                           |
| :------------- | :---------------------------------------------- |
| [Color](#color)       | Average color value. If the operation fails, **null** is returned.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts: image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
      let color = colorPicker.getAverageColor();
      console.log('get average color =' + color);
    }
  })
})
```
![en-us_image_Average_Color.png](figures/en-us_image_Average_Color.png)

### isBlackOrWhiteOrGrayColor<sup>10+</sup>

isBlackOrWhiteOrGrayColor(color: number): boolean

Checks whether a color is black, white, and gray.

**System capability**: SystemCapability.Multimedia.Image.Core

**Parameters**

| Name    | Type        | Mandatory| Description                      |
| -------- | ----------- | ---- | -------------------------- |
| color| number | Yes  |  Color to check. The value range is [0x0, 0xFFFFFFFF].|

**Return value**

| Type          | Description                                           |
| :------------- | :---------------------------------------------- |
| boolean              | Returns **true** if the image is black, white, and gray; returns **false** otherwise.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts: image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
      let bJudge = colorPicker.isBlackOrWhiteOrGrayColor(0xFFFFFFFF);
      console.log('is black or white or gray color[bool](white) =' + bJudge);
    }
  })
})
```

## Filter

A class used to add a specified effect to an image. Before calling any method of **Filter**, use [createEffect](#effectkitcreateeffect) to create a **Filter** instance.

### blur

blur(radius: number): Filter

Adds the blur effect to the filter linked list, and returns the head node of the linked list.

**System capability**: SystemCapability.Multimedia.Image.Core

**Parameters**

| Name| Type       | Mandatory| Description                                                        |
| ------ | ----------- | ---- | ------------------------------------------------------------ |
|  radius   | number | Yes  | Blur radius, in pixels. The blur effect is proportional to the configured value. A larger value indicates a more obvious effect.|

**Return value**

| Type          | Description                                           |
| :------------- | :---------------------------------------------- |
| [Filter](#filter) | Final image effect.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
};
image.createPixelMap(color, opts).then((pixelMap) => {
  let radius = 5;
  let headFilter = effectKit.createEffect(pixelMap);
  if (headFilter != null) {
    headFilter.blur(radius);
  }
})
```
![en-us_image_Add_Blur.png](figures/en-us_image_Add_Blur.png)

### brightness

brightness(bright: number): Filter

Adds the brightness effect to the filter linked list, and returns the head node of the linked list.

**System capability**: SystemCapability.Multimedia.Image.Core

**Parameters**

| Name| Type       | Mandatory| Description                                                        |
| ------ | ----------- | ---- | ------------------------------------------------------------ |
|  bright   | number | Yes  | Brightness value, ranging from 0 to 1. When the value is **0**, the image brightness remains unchanged.|

**Return value**

| Type          | Description                                           |
| :------------- | :---------------------------------------------- |
| [Filter](#filter) | Final image effect.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
};
image.createPixelMap(color, opts).then((pixelMap) => {
  let bright = 0.5;
  let headFilter = effectKit.createEffect(pixelMap);
  if (headFilter != null) {
    headFilter.brightness(bright);
  }
})
```
![en-us_image_Add_Brightness.png](figures/en-us_image_Add_Brightness.png)

### grayscale

grayscale(): Filter

Adds the grayscale effect to the filter linked list, and returns the head node of the linked list.

**System capability**: SystemCapability.Multimedia.Image.Core

**Return value**

| Type          | Description                                           |
| :------------- | :---------------------------------------------- |
| [Filter](#filter) | Final image effect.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
};
image.createPixelMap(color, opts).then((pixelMap) => {
  let headFilter = effectKit.createEffect(pixelMap);
  if (headFilter != null) {
    headFilter.grayscale();
  }
})
```
![en-us_image_Add_Grayscale.png](figures/en-us_image_Add_Grayscale.png)

### getPixelMap

getPixelMap(): [image.PixelMap](js-apis-image.md#pixelmap7)

Obtains **image.PixelMap** of the source image to which the filter linked list is added.

**System capability**: SystemCapability.Multimedia.Image.Core

**Return value**

| Type          | Description                                           |
| :------------- | :---------------------------------------------- |
| [image.PixelMap](js-apis-image.md#pixelmap7) | **image.PixelMap** of the source image.|

**Example**

```ts
import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
};
image.createPixelMap(color, opts).then((pixelMap) => {
  let pixel = effectKit.createEffect(pixelMap).grayscale().getPixelMap();
  console.log('getPixelBytesNumber = ', pixel.getPixelBytesNumber());
})
```